Returning to the hobby after about 15 years away... setting up a 29 gallon planted aquarium. It's been cycling for the past couple months and last week I purchased my first fish. I got 5 Colombian, 4 small Von Rio tetras and 6 corys. My question is about mixing the tetras... they seem to hang out together and the Colombians never bother the Von Rios, only chase each other. I want to get more Von Rios when they are available, but now am concerned that the Colombians will get larger and the 29 might seem cramped. If that happens, I assume they may get more aggressive. Should I add more Colombian tetras to reduce their chasing behavior? Or will adding more Von Rios make all the tetras feel more secure?